My guess is that the teacher assigned this so that students would experience reactions and over reactions since they are ASL students. Success.
Hey, OP, if this is true, you should tell the forum once the teacher explains it to you. This sounds like a fascinating but highly insensitive social experiment. I can understand wanting to send a student off to say something offensive and show you the reaction, but that's not just cruel to the student, it's cruel to the D/deaf posters who just found out that someone still thinks it's okay to question their position as part of humanity and whether it's okay to have more of them in the next generation. Leaving aside what ambrosia explained better than I could about why this isn't even a feasible way to get rid of deafness if we did want to, the question goes beyond just asking whether deafness is something to try to prevent. It asks whether deaf people should be ALLOWED to marry and produce deaf offspring. So not only is the question about the desirability of deafness as a trait, the question implies that it's okay for the majority to decide to curtail basic rights and freedoms of the minority in order to prevent more of said minority from being born.
So, OP, you just went on a forum of mostly deaf (and largely Deaf) people and asked "is deafness horrible enough that we can treat you like second-class citizens in order to avoid having more of you in the next generation?"
Maybe you didn't come up with the question, and if so, it was at best pretty thoughtless of your teacher to make you ask it, but on the other hand, you really should be able to understand why people are angry.
Personally, I'm laughing because I'm not going to get worked up about someone whose opinions have been that thoroughly discredited. Eugenics on that scale will never get anywhere, not when it's so easy to just say "Hitler did it" and avoid giving an actual counterargument. Which isn't because there aren't any to be made. There are lots, like: but it won't work! But it wouldn't stop people from entering relationships with each other anyway! But if they breed with the hearies instead, it'll spread deaf genes through a greater percentage of the population, not a smaller one! But even if we accept that it's undesirable, surely it's not so undesirable that it's worth breaking people's hearts over!
Oh, and since you're printing this thread out and showing your teacher (I hope this shows my username, too; I wouldn't want to pass as qualified when I'm not), this is a note for them: social experiments of this form are impolite because they cause friction and mistrust between people. The question is also not acceptable as a serious topic of debate now because it's no longer controversial. If you don't know that, you need to spend some time getting acquainted with certain recent societal changes before you teach your next class.
(Hang on a second. OP, are you living in some kind of third-world country where this is still up for debate? Because if so, then it could be a much more reasonable thing to assign you to do. If wanting to prevent deaf people from marrying is considered a legitimate position in your area, then asking about it on a forum full of D/deaf people is probably the best thing you could do, because hey, they ARE the experts on DHH issues, right?)